<!DOCTYPE html>
<html>
<head>
<style>
:root {
  --blue: red;
  --white: blue; 
}
body {
  background-color: white;
}

h2 {
  --white: red;  
  border-bottom: 3px solid var(--white);
}

.container {
  color: #1e90ff;
  background-color: white;
  padding: 25px;
}

button {
  background-color: var(--white);
  color: #1e90ff;
  border: 1px solid #1e90ff;
  padding: 5px;
}
</style>
</head>
<body>

<h1>传统方式</h1>

<div class="container">
  <h2>Welcome to Shanghai!</h2>
  <p>Shanghai is one of the four direct-administered municipalities of the People's Republic of China.</p>
  <p>Shanghai is one of the four direct-administered municipalities of the People's Republic of China.</p>
  <p>
    <button>Yes</button>
    <button>No</button>
  </p>
</div>
<script>
    var a=1;
    function fn(){
        var a=2;
        alert("a="+a);
    }
    fn();
</script>

</body>
</html>
